Connecting Multiple Charge Controllers one Battery Bank

Here you are, asking yourself the question, Can I charge a battery bank with two charge controllers?

YES! You can add as many charge controllers as you want! Keep on reading this article to find out how.

Here are some reasons why you might want to add another charge controller:

  • You want to add more solar panels to your system.
  • You want to add a panel with a different specification than the one you already got.
  • You want to separate panels from each other because they receive shade at different times of the day.

Now your next question might be: do they need to communicate with each other?

How do Charge Controllers Interact With Each Other?

Charge controllers sense the internal resistance of a battery and send their current to the battery terminals based on the resistance of the battery. If the battery is at a low state of charge, the resistance will be low and the charge controller will charge in bulk mode (depending on the battery type).

If the resistance increases, the charging current will decrease because the battery is almost full.

If two or more charge controllers charge the same battery, the battery will be charged quicker. The multiple charge controllers will not compete with each other because they all sense the same internal resistance of the battery. If charge controller A puts in 100Watts, charge controller B will also put in 100Watts into the battery.

When you program your charge controller you can add the cutoff voltage in the software. That means if your battery reaches a pre-defined voltage, it will stop charging. You can tell charge controller A to charge to 12 volts and charge controller B to charge to 12.8 volts. This is not needed but is good to know because one charge controller might stop charging if it reaches that point, and you will be wondering why that is. Also, if the wires of charge controller A are a bit longer, it might enter float mode earlier than charge controller B because of the voltage drop (increased resistance).

If the charging current becomes too high, the internal resistance of the battery will change because of the heat generated. The charge controllers will then reduce their power input to the battery.

Wiring Two Strings to Two Charge Controllers

In this example, there are two strings or arrays of solar panels that go to every charge controller. This setup is ideal if you have multiple solar panels that do not have the same rating. Refer to the article about series and parallel wiring solar panels if you want to know more about how to wire your panels, or check out my video.

You can also use this kind of setup on a boat. If one charge controller is in the shade of a sail, but the other is in full sunshine, the sunny panel will still deliver its max power. The shaded panel will deliver reduced power. This is very similar to wiring your panels in parallel.

diagram on connecting 2 solar charge controllers to 1 battery
diagram on connecting 2 solar charge controllers to 1 battery

 

Synchronizing Multiple Charge Controllers

If you are using two or more charge controllers they do not need to be able to communicate with each other.

There might be a problem with flooded lead-acid batteries where they equalize every month. If you have multiple charge controllers attached to the battery bank they equalize more frequently, Which is not good for the battery. You need to turn off the equalizing function on the other charge controllers so you only have one charge controller performing the equalize function.

Some models are able to communicate with each other like the Victron BlueSolar and SmartSolar models. The communication happens with the built-in Bluetooth module for the SmartSolar model. For larger systems, they recommend using the VE.can port.

The reason for communication between charge controllers is so that only one charge controller will balance the cells, not all of them (only with lead-acid).

Both charge controllers will deliver their maximum amount of current to the battery.

Maximum Charge Current

Lead-acid batteries can only be charged at a low C-rate (0.2xAh capacity). while Lithium batteries can be charged at a higher C-rate (1xAh capacity).

For example, you can efficiently charge a 100Ah lead-acid battery with a current of 20Amps, or a 100Ah lithium battery with 100Amps.

You need to take this into consideration. If the charging current will be higher than those rates, the energy will be dissipated as heat or the BMS (battery management system) will limit the current going in the battery. Make sure your battery capacity (Ah) is high enough to accommodate another charge controller.

Can I use a multiple input charge controller?

Many people find it attractive to have one charge controller to which they can connect mixed solar panels. However, this is not a good idea for redundancy. What happens if the one device that charges everything is broken? Another problem is availability. Most of the time it will be hard to find one according to your specifications. Therefore it’s better to have multiple separate charge controllers.

Conclusion

You can wire multiple charge controllers in parallel to support an expanding solar system. You do not need to have charge controllers that are able to communicate with each other but you should only enable the equalizing function in one of them if you have flooded lead-acid batteries.

That’s how you connect 2 charge controllers 1 battery bank. Hope this article was helpful!

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52 thoughts on “Connecting Multiple Charge Controllers one Battery Bank”

  1. Solar panel array to multiple charge controllers (parallel) and one battery bank. Just about every other article I have read about this states that it is not a good idea to do this and that each PV array should be connected to each MPPT controller independtly. I was looking to use two identical solar controllers in parallel with one PV array, but I am slightly confused as to weather this will work OK?

    Regards,
    Graeme

    Reply
    • Hello Graeme.
      This is not the most effective method to wire your solar panels to the charge controller. If the whole PV array is facing the same direction, this method will work. The problem is when something happens to the array. If one solar panel gets damaged or shaded, it will influence the whole power output of the array, which will affect performance. It’s not the most efficient way, but it will work. I recommend wiring it like the second image. I have updated the article too.

      Reply
  2. Fascinating and well explained !
    I’m thinking of the following and not sure if it’s a workable idea or not.
    This would be to harvest as much daylight during winter … (summer supply/consumption should be easily met). House only has 4x250w at the moment and cannot meet very miserly use in winter. 24v system, large lead acid forklift battery.
    Planned … barn roof installation.
    South facing: 2 x 370w in series plus the same in parallel (4 panels total) with 40a MPPT
    West facing: the same as above

    Both outputs of the MPPT controllers to feed one pair of heavy duty copper cables running to the battery 16m away.

    Arrays planned for redundancy and resilience with panels being manually isolated in extreme sunlight (if needed) or switched to a separate battery bank (if the future requires it). Potentially Heath Robinson but truly modular in scope.
    Would this system seem plausible ?

    kind regards
    Duncan

    Reply
    • We have to know that light intensity affects the amperage, and temperature affects the voltage. Knowing this, we can predict that the two panels facing south would deliver a higher current than those facing west. This means that those two series strings should be placed in parallel to make a hybrid connection, just like you said. Because in parallel connections, the amps add up while voltage stays the same. Make sure the voltage drop stays under 3% for those 16-meter cables. Place your charge controller as close to the battery as possible. Check voltage drop video here: https://www.youtube.com/watch?v=d9ByUjphO6A&ab_channel=cleversolarpower

      Reply
  3. Hi Nick,
    I first want to commend you on probably the finest book (Off-Grid Solar Power Simplified) I have come across so far on the subject of Solar Power Systems. It has been extremely helpful to have a complicated subject explained probably as best as one could explain it. Thank you

    One question I have wondered and was not answered to my satisfaction (by a company tech). I will soon have 8 X 100 Watt Renogy mono panels to a 60 Amp MPPT Renogy Charge Controller and using 540 Ah Lithium battery bank (I am going to make my own Lithium battery from online community you suggested). I asked if there was some way I could add a future wind mill. I was told they didn’t have provision for multiple power inputs, therefore not possible. But reading your article above it sounds like I can add a wind mill to a second charge controller (sized for the wind mill of course, I assume it doesn’t need to be the same size as my other charge controller, but it will be an MPPT) and then wire both charge controllers in parrallel to the battery? How does that sound? And I have a creek that runs outside my window. My goal also was to have some kind of micro-hydro someday. Therefore add another charge controller for that and wire in parallel to same connections as others. I believe I read somewhere in your writtings it would be best to have all charge controller cables the same length? And since I am using Lithium I don’t have to worry about changing any settings (like turning off equalizing, or setting voltage cutoffs to different levels, etc.). Thank you for your help

    Reply
    • Hello Andy, Thank you for your compliment about the book. I really appreciate that. I’m sorry for the late reply, I was on vacation.

      Coming back to your question, it’s not a problem to have multiple charge controllers in parallel charging your battery bank. The cables from the charge controller to the battery bank can have different lengths.
      The thing you need to make sure of is the maximum charge current that your battery bank is able to absorb. Let’s say your DIY LiFePO4 battery can absorb a maximum current of 100 amps, then all your charge controllers combined shouldn’t deliver more than 100 amps, otherwise, your BMS will shut down.

      What voltage will your system be?

      Reply
  4. Dear Nick,

    First of all thank you very much for your informative and helpful writing.

    I would appreciate, if you can share your thoughts on my subject as explained below:

    I installed an Off-Grid Solar, Wind and Battery connected parallel to each other a month ago. Solar panels(3.6kWp) are connected to Growatt SPF5000 off-grid inverter. The Wind turbine(3.3kW at 14m/s) has its own Charge Controller with 48Vdc output. The battery is also from Growatt with 3300Wh capacity, LiFePO4 type, communicated via CAN with the Solar Off-Grid Inverter. The Battery, Wind Charge Controller and Off-Grid Solar Inverter outputs are connected in parallel to a 48Vdc busbar in a panelboard. But so far no loads have been connected to the system. Only the internal consumptions of the devices use energy from the battery.

    I have been monitoring the behavior of the system for a few days through the monitoring system of the inverter and observed that the Wind Charge Controller is not charging the battery. In a normal day time, when the battery goes down to %95 SOC level, It is charged back again to %100 SOC with the Solar inverter. As the PV Modules are not generating energy at night, the level of the battery is going down to around %70 SOC level (due to internal consumption of the battery). When the Solar Energy becomes available in the early morning, the battery starts being charged back to %100 SOC. I am trying to find out, why the battery is not being charged wind turbine charge controller? I might be hard for you to figure out system in detail, but incase you need further detail, I can share.

    Best regards,
    Alper

    Reply
    • Hello Alper,
      You have explained your system well, I will try to give you a few tips.
      – Can you measure the amps going from your wind charge controller to the busbar?
      – The internal consumption of the battery is very low. If you go from a 100% to 70% SOC without appliances on, there is something wrong.
      – Could it be that the charging/discharging system voltages are different on the wind turbine than the growatt hybrid?
      – it could be that the wind turbine has no chance of charging up the battery because it doesn’t reach a low enough voltage.
      – Is the wind controller suited for LiFePO4 batteries?

      Reply
  5. Hi There,

    I appreciate this so much! I’m using this set up to wire my solar panels to 2 Epever MPPT charge controllers. Since purchasing the first charge controller, I’ve changed my setup considerably and needed a second.

    Like the charge controllers in your diagram, I chose this controller because I could wire the load directly to it and control the battery discharge this way. But now I’m wondering, how do I wire the load if I have 2 charge controllers with this capability and 1 battery?

    I hope this isn’t the silliest question. Thank you so much for your time.

    Clare

    Reply
    • Hello Clare, There are no silly questions, only silly answers and I hope mine isn’t one of them.
      – I do not recommend connecting your load to the charge controller. Instead, I recommend connecting your loads to the main battery terminals. Especially if you have a big setup like yours. You need to use a low voltage disconnect between the battery and your load, this will work the same way as your charge controller. The difference is that you can draw more amps because the output on the charge controller is limited.
      – If you still use the load terminals on the charge controller, then using one charge controller is fine if it meets your current demand. The current on these outputs is severely limited.
      Hope this helps.

      Reply
  6. Hi Nick,

    Thanks for the informative web pages! Good reading.

    Similar to the question of using multiple charge controllers, I was wondering about hooking a small battery charger or trickle charger to a battery bank that is also charged by solar panels and a charge controller.

    Specifically, on my off-grid studio I have a 4×100 watt panels, with single 12V 30a solar charge controller connected to a small battery bank (3x 100ah AGM batteries in parallel). After continuous rainy days the batteries get depleted because there simply isn’t enough sun. However, the studio is close enough to my house that I could run an extension cord if need be.

    Can I hook a small auto battery smart-charger to the batteries, maybe a trickle charger (5a or less), to work in tandem with the solar charger? Just to keep the batteries topped off during bad weather. Would this damage the solar charger or would they play well together?

    Thanks!

    Reply
    • Hello Glenn, Ideally you need a low voltage disconnect so the batteries don’t get depleted under a certain voltage. as soon as there is sun, the batteries get charged again.
      You can use your extension cable to run your appliances this helps reduce the cycles on your battery. But adding a trickle charger to a battery bank wouldnt be a problem I think. I haven’t tried it myself, so no guarantees from me.

      Reply
      • Thanks for the reply.

        Welp, I’ve tried it now for a few weeks — added a 2amp charger to the system, and plugged it in as necessary. Doesn’t seem to hurt anything, and keeps the batteries topped-off. Charge controller doesn’t appear to mind.

        Cheers.

        Reply
  7. Hi Nick
    Thanks for your article, just wanting to clarify.
    I have an existing solar setup with a 100W 6A panel and with an 8.8A AGM charge controller and am looking at adding a 160W 9.5A panel that has a 15A MPPT controller as a friend is dissembling their system.
    Will the lower current AGM reduce the capacity of the MPPT controller if wired up like shown in your article?
    Thanks

    Reply
    • Hello Andrew, there shouldnt be a problem with wiring two charge controllers together to charge one battery. The AGM will deliver a lower current than the new one, but both will charge the battery. The battery is charged according to internal resistance.

      Reply
  8. So many people get this wrong. I have a setup like that since I need more panel capacity during monsoon season than inverter output. I have four sets of panels connected to four different charge controllers and will soon be adding a fifth. I have a 12kw inverter and I’m not using the built in charge controller, just the ones connected to the battery bank. It works perfect. They all sinc with each other and charge about the same. You can tell when clouds pass over as the power changes slightly at different times on each controller. I set all of them the same and they reach maximum charge about the same time. No issues in almost 2 years.

    Reply
    • Hello Richard, thanks for your comment. You are saying your charge controllers synch with each other. What charge controller are you using?

      Reply
  9. Thanks Nick,
    How do I connect my 24 pieces 300watts each solar panels to two 100A PWM and 60A MPPT charge controller to charge my 24V, 1200AH battery bank for my 24V inverter system for optimal power output?

    Reply
    • Hello Felix, I recommend using a 48V system, but that won’t be compatible with your PWM charge controller. I would switch out the PWM charge controller for a MPPT, so you don’t lose 20-30% of your generated power. If you want to keep using the PWM charge controllers, then you need to check what kind of battery that you are using, and if they are able to ‘take’ all the current you are sending into them. If you are using lithium, you need to make sure the PWM charge controllers are compatible. If you have lead-acid, they cannot be charged more than 0.2C (which looks ok with 1200Ah). on paper, you are going to be pushing 300amps into the battery (less in practical situations). With PWM controllers, you need to match the panel’s voltage close to the battery voltage. This means that you have to parallel the panels, which will make it a huge cost for wiring. The cost of the wiring can offset the cost of two or more MPPT controllers. With MPPT controllers, you can put your panels in series, which saves on wiring costs.

      Reply
  10. Hi Nick,
    Thanks for another interesting, well explained article.
    I appreciate that you give extended answers on all kinds of questions.
    I will keep an eye your channel.

    All the best,
    Ray (Yes the one from France)

    Reply
    • I have not tried that before, but I don’t think it’s going to be a problem. As long as both are set correctly for the battery type you have. Make sure that the charging C-rate of the battery is equal to or lower than the specified charging C-rate of the battery.

      Reply
  11. Hi Nick,
    Thanks for the Info and all the answers you gave to everyone.

    I have a question for you, I am setting up a Power system for my Camper parked up in the woods about 5 miles from power lines.
    I am going to use a combo of Solar Panels with batteries and a small inverter gen set.

    What I have now is:

    8 – 100ah AGM 12 volt batteries will be hooked in parallel for 800ah

    3000/6000 watt Pure sine inverter 12 volt dc in 120 volt ac out

    Camper has 55 amp dc power converter came with the 2003 Keystone Montana 3575

    Westinghouse iGen4500 3700/4500 120 volt inverter generator

    Transfer switch for Generator/ shore power to Inverter

    What I am planning on getting to start with is:

    6 – Monocrystalline 100 watt 12 volt Solar Panels Hooked Parallel using a 60 amp MPPT controller ( will add to up to 8 panels )

    Question is do you see a problem with me using the Campers power converter in parallel with the solar controller so that when I am using the Generator I can also add charge to the bank of batteries to keep batteries up.

    Thanks
    Shane

    Reply
    • Hello Shane,
      Do not use 12V with an inverter over 1000W. If you use 12V and a 3000W inverter, you will need a cable able to carry 250amps. That is unfeasible in a DIY system.
      I recommend configuring your system for 48volts so your current stays under 100amps in your DC wiring. Why would you wire your panels in parallel? Contact me on my email and we can talk more.

      Reply
  12. Hi Nick!

    I have to buy second, (more Amps) controller for separate pv panels but one battery bank.
    Can i buy different brand MPPT or better same manufacturer?

    Reply
    • Hello Bart,
      You can get any MPPT charge controller. As long as you are selecting the right charging profile it’s going to be ok. Some manufacturers might have a different charge profile for different chemistries. Check out the recommended charge C-rate for your batteries. Do not go higher than that. Otherwise, increase the capacity (Ah) of your battery to increase charging and discharging C-rate.

      Reply
  13. Hello

    I have a 4.8Kw off grid system with one 60 amp MPPT midnite charge controller. 48V Lifepo4 batteries

    On sunny days the charge controller hits an Amp Limit of about 60 Amps and it says we are generating about 3100 Watts.

    Am I losing potentially 1700 Watts and would a second charge controller solve this problem?

    Reply
    • Hello Colin,
      We have to take into account that the 4.8kw array is never going to deliver the 4.8kw. This is in ideal conditions.
      But I would definitely add another charge controller. You are losing out on energy. Another 20amp controller will be sufficient.
      Theoretically, your panels can put 92Amps into the battery. (4800/52V=92A). Use 80% efficiency factor and you will have an additional 13.8A being wasted. It’s up to you if that is worth the investment and the rewiring of your panels.

      Reply
  14. Thanks Nick,
    This is very useful and much clearer than a lot of other explanations.
    I’m looking to add another 20A controller rather than buying a 40A one, but my question is whether there is a way of monitoring the two of them together – rather than having to constantly check them both and calculate what is going on.
    Graeme (in the bush in NZ)

    Reply
  15. Hello, I was looking to attach multiple charge controllers to single battery bank and found this guide.
    I have 250wx6 pannels attached to a 48v system with 4x12v battery bank making it a 48v system. All is connected to a hybrid solar inverter that oprates at 48v. It has pwm built-in charge controller.
    Now when i want to add more solar to the inverter I face the issue of not finding same 250w pannels because everyone now selling high wattage pannels like 450w 520w so Can’t attach those panel to my system.
    Everyone I talked to asked my to get a new inverter with dual charge controllers but no one talks about connecting different set of pannels through a separate charge controller to same battery bank and use both older and newer pannels instea6of spending a fortune on buying new hybrid inverter and new pannels.
    My question : If I buy new pannels and attach a separate charge controller to then and add them to the same battery bank, is it possible to get output from the old inverter??
    Will the oleder system and new attached pannels work together to support the load going out from the inverter i have?

    Reply
    • Hello Aswad.
      Very structured question, I like that.
      You can add the second charge controller to the battery bank. The inverter will still draw power from the battery. The battery will now get charged quicker. That’s why you need to make sure the charge rate of your battery can handle the new panels (charge c-rate). Don’t forget to adjust the settings of the new charge controller.

      Reply
      • Dear Nick,

        I have a very similar setup, but the system is 24V instead of 48V with two 220Ah lead-acid tubular batteries. I am unable to connect any Solar panels to my 3.5kw solar inverter, since the inverter’s charger is rated to 120V – 500V, and I do not have space to install 3-4 large high wattage panels ( 540-600W).

        I am not willing to go off-grid ( since I do not have enough space for the needed panels). I just need to install a few small ones all around the house just to lower my electricity bill a bit.
        In the meantime, I just charge them using Utility.

        Would it be possible for me to install an external solar charger parallel to the solar inverter to the same battery bank? If yes, I have my solar inverter settings as follows:
        -Bulk Charge 29.2V
        -Float Charge 28.2V
        -Cut-Off voltage 21.5V
        -Maximum Charge Current 40A

        How should I configure my new solar charger so that I do not damage any of the equipment (Inc. Batteries).
        I would highly appreciate your recommendations, even to changing my current Solar Inverter Settings.

        Best Regards,
        Michel

        Reply
        • Hello Michel,
          You can add another charge controller to the same battery bank. Make sure the additional solar panels are pointing in the same direction and at the same tilt. You need to calculate if the charging C-rate is still ok for your batteries.
          Currently, charging at 40A and a 220Ah battery is ideal (0.2C-rate). Depending on the chemistry, this can increase a little bit. If you want, you can send me an email with your schematics so I can get a better look.

          Reply
          • So, If I install one 350W panel with its own solar charger, will it interfere or damage anything on the long run?

            Thank you so much for your help…

            And one last thing, what should the charger’s settings be to work with the settings of the solar inverter mentioned above?

  16. I am building a solar setup for my boat lift that I would love to charge my boat while it is sitting on the lift unused. I have a 24v panel to a pwm controller that will be connected to 2x12v batteries in series. That part is simple. Where I run into my lack of experience is being able to use that for 12v shore power to charge my 2x12v in parallel(isolated at rest) in my boat. My original idea is using a 24v-12v step down and use that as a shore power. Is that going to cause issues with the charge controller? It doesn’t need to be super robust as my boat will easily charge the batteries during a day doing water sports, I’d just like that extra peace of mind.

    I had considered just getting a separate 12v setup specifically for my shore power, but I read that leaving the panel not connected to anything and reconnecting it in the wrong order can cause issues. Seems simple to avoid, but trying to take any margin of error out of the equation so anyone not me can handle it.

    Thoughts?

    Reply
    • Does the 24V panel charge your battery? With PWM charge controllers, the voltage needs to be greater than the battery voltage since PWM controllers are not voltage converters.
      I would get another PWM charge controller to charge the battery of your boat separately. Ideally, you would have two 18V panels connected in series. When you charge your 24V battery, connect them in series and when you charge your 12V battery, put them in parallel. This can be easily done with mc-4 connectors. That is if I understood your question correctly. If not, send me an email with a schematic.

      Reply
      • Or would it be better/easier to connect two charge controllers to the 24v panel? I could run an MMPT for the 24v panel step down to the 12v bank since I know that is more efficient. I think I was greatly overcomplicating this in my mind by introducing too many pieces.

        Reply
  17. Thanks Nick – for your advice a month or three back.
    I’ve finally got around to installing a second MPPT controller and the first of a second array of panels.
    It all seems to be working fine, but my controllers seem to be a bit confused by it all. Nothing was working properly until I shifted the load from the controller ports to a direct line from the battery bank and now they are working, but giving error messages about the load. They are both Epever/Tracer controllers – one an AN series the other an Xtra N series. I don;t think it is a real problem – just a bit annoying/disconcerting.
    Does this sound right to you?
    thanks in anticipation.
    Graeme (in NZ)

    Reply
  18. Hi there,

    I’ve tried many ways to connect multiple solar charge controllers to one battery bank and did notice that only ONE of the controllers was putting power into my battery bank, the other went in idle mode.

    As i connected a couple of shunts between the solar panels and the controllers to see how much power each controller put in the battery..

    Everytime i see the same, one is filling my battery with 3/4amp and the rest is put to sleep.

    If you wish, i can show you my setup and discuss about it!

    Thanks in advance

    Reply
    • 1: Check if your charge controllers have the same setup. Make sure everything is the same.
      2: Charging with 4 amps is not much. Maybe your batteries are always full and the other charge controller doesn’t kick in.
      3: There would be no reason why it shouldn’t work. It’s the same as having two chargers on a battery. They charge based on internal resistance, not voltage.
      4: contact me on my email if you tried the above and it’s not working.

      Reply
  19. Hello Nick, Thank you for sharing this information. I am learning new thingsmevery day in my solar journey. I have a few questions about the wiring of batteries, and solar arrays.

    Equipment is as follows.
    2 growatt SPF 3000 TS LVM-ES 48v
    Batteries will be have self wired BMS from overkill 16s 100a for a total of 4 GYLL batteries, with a 200 TS class fuse off of 2 positive terminals to a 4 position bus bar.
    First question is: can I wire 2 of the batteries in parallel x 2 and run both of the positives to a bus bar terminal, and like wise for the negatives? Or is it better to wire all 4 batteries in parallel with only 1 positive, and 1 negative?

    I was planning on running my PV array as follows. 4 390 watt bifacial panels run in series to 1 controller, and 8 250 watt panels run in series with 2 strings, to the second controller. Question: is it ok to run a series and parallel like this? Each controller will not exceed 80a on the parallel strings, and will not exceede the volts 250 on the series string. When adding 2 different arrays does this effect each controller individually, or do you need to stay below the 250 v 80 amps with both arrays combined? I am guessing that each controller is capable of 250v 80 amps individually. My arrays where calculated with a solar array calculator, and take in to consideration voc at potential lowest temp of -40f as I live more North. Hopefully this makes sense.

    Thanks again Nick, your article helped me learn something new today for wiring the 2 units together.

    Mark

    Reply
    • Hello Mark, Will did a video about this: https://www.youtube.com/watch?v=oXBT8lSC25M
      Second question: the current on the charge controller is what goes into the battery, not what is accepted at the input. I think you confused these two. So a 250V 80A charge controller can have a max of (48V*80A) = 3800W of solar panels (theoretically). Each controller is capable of 250V 80A individually. Having multiple batteries will solve the problem with C-rate. If you have more questions, send me an email.

      Reply
  20. Came across your website and wondered if you could answer my question. My situation is simple but I simply do not have the knowledge to make a proper determination.
    I own an RV, a fifth wheel to be exact. My idea was to hook up a portable solar suitcase from Renogy directly to the battery to help keep my deep cycle (lead flooded) battery charged during periods of time when we are off of shore power. I ordered a 200 watt solar suitcase w/ pwm 20 amp charge controller. What I received was two 100 watt suitcases, each with its own pwm 20amp controller. So, my question is can I just run them in parallel to a 12v battery without burning, melting, or otherwise ruin, anything?

    Reply
    • Hello Aimee, It’s not going to be a problem. As explained in the article, they charge on internal resistance. Both of them will charge the battery at the same time. Make sure the correct batteries are selected in the PWM controller.

      Reply

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